Capitol Reef National Park Air Quality Information
Both local and distant air pollutant sources affect air quality in Capitol Reef NP. Nearby large point sources include power plants, refineries, and lime kilns in Coconino County, Arizona, and Clark County, Nevada. Pollutants also travel greater distances to the park from both mobile and point sources throughout the Southwest.
The air quality related values (AQRVs) of Capitol Reef NP are those resources that are potentially sensitive to air pollution, and include vegetation, wildlife, water quality, soils, and visibility. At present, visibility has been identified as the most sensitive AQRV in the park; other AQRVs may also be very sensitive, but have not been sufficiently studied. Although visibility in the park is still superior to that in many parts of the country, visibility in the park is often impaired by light-scattering pollutants (haze).
As part of the Interagency Monitoring of Protected Visual Environments (IMPROVE) network, visual air quality in Capitol Reef NP has been monitored using an aerosol sampler (2000-present), and a 35mm camera (1983-1991). The U.S. Environmental Protection Agency’s Regional Haze regulations require States to establish goals for each Class I air quality area to improve visibility on the haziest days and ensure no degradation occurs on the clearest days. The data record at Capitol Reef NP (from the aerosol sampler) is insufficient to analyze temporal trends. However, an analysis of 1990-1999 data from parks throughout the Colorado Plateau region indicate that visibility is improving somewhat on the clearest days, but degrading on the haziest days.
Surface waters in Capitol Reef NP are well-buffered and, therefore, not likely to be acidified by atmospheric deposition. A special study of rock pools was conducted at three locations in the park: Cottonwood Tanks, Muley Tanks, and Fountain Tanks. All had very high acid-neutralizing capacity (500-1230 microequivalents per liter). Most soils are also likely to be well-buffered from acidification.
Soils and vegetation in the park may be sensitive to nutrient enrichment from nitrogen deposition. In some parts of the country, nitrogen deposition has altered soil nutrient cycling and vegetation species composition; native plants that have evolved under nitrogen-poor conditions have been replaced by invasive species better able to utilize nitrogen. Studies that may have applicability to Capitol Reef NP are underway in nearby Canyonlands NP to investigate nitrogen effects on soil dynamics, exotic plant invasiveness, and biological soil crusts.
Deposition of pollutants, including sulfur and nitrogen, is not measured in Capitol Reef NP. However, information from deposition measurements at Bryce Canyon NP and Canyonlands NP can be used to estimate deposition at Capitol Reef NP. Wet deposition has been monitored in Bryce Canyon NP (1985-present) as part of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). The site ID is UT99. Dry deposition rates have been estimated for Canyonlands NP (site CAN407), 1995-present, as part of the Clean Air Status and Trends Networks (CASTNet). Rates of atmospheric deposition of nitrogen and sulfur are relatively low in these parks, but elevated above natural conditions. Trend analysis by NADP shows that annual wet nitrogen deposition has increased from 1985-present in Bryce Canyon NP; sulfur deposition has slightly decreased. A CASTNet analysis of site data for 1995-2001 indicates that annual dry deposition of nitrogen has remained steady in Canyonlands NP; dry deposition of sulfur has decreased slightly. Other parks on the Colorado Plateau show similar trends, with nitrogen deposition increasing or staying the same, and sulfur deposition decreasing.
Several plant species that occur in Capitol Reef NP are known to be sensitive to ozone (e.g., Populus tremuloides, Amelanchier alnifolia, and Pinus ponderosa). Long-term average ozone concentrations have been monitored in the park using a passive sampler. Information can also be extrapolated from continuous monitors at other parks in the region, which indicate that ozone concentrations and cumulative annual ozone doses in the Colorado Plateau fall within a range that may produce visible effects or growth effects on sensitive plant species. In addition, data from 1990-1999 indicate that ozone concentrations are increasing throughout the Southwest. In 1999, the National Park Service Air Resources Division surveyed vegetation in several Utah parks, including Zion NP, Cedar Breaks NM, and Bryce Canyon NP, and found symptoms of ozone injury on vegetation at all three parks.
Although the small potholes may be insensitive to acidic deposition, they may experience nutrient enrichment from nitrogen deposition, resulting in algae blooms and oxygen depletion. Soils in the park may be similarly affected by nitrogen enrichment. In some parts of the country, nitrogen deposition has degraded water quality and altered soil nutrient cycling and vegetation species composition. There is no information available on the effects of nitrogen deposition on waters or soils in the park. However, studies are underway in nearby Canyonlands NP to investigate nitrogen effects on soil dynamics, exotic plant invasiveness, and biological soil crusts.
Information from wet (i.e., rain, snow) and dry (i.e., dust, dryfall) deposition samplers at Canyonlands NP can be used to characterize conditions in Arches NP. Wet deposition is monitored in Canyonlands NP (1997-present) as part of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). The site ID is UT09. Rates of atmospheric deposition of nitrogen and sulfur in rain are relatively low in Canyonlands NP, but elevated above natural conditions. The data record is insufficient for a detailed trends analysis. Other Colorado Plateau NADP monitoring sites show decreasing trends in wet sulfur deposition from 1990-1999; for wet nitrogen deposition, some sites show a decreasing trend, while others show an increasing trend. Dry deposition rates are estimated for Canyonlands NP (site CAN407), 1995-present, as part of the Clean Air Status and Trends Networks (CASTNet). Data indicate that, for the period 1999-2001, dry deposition contributed about 60 percent of total inorganic nitrogen deposition and about 50 percent of total sulfur deposition. A CASTNet analysis of site data for 1995-2001 indicates that annual dry deposition rates of nitrogen have remained steady; dry deposition rates of sulfur have decreased slightly.
Additional information relative to air quality and air quality related values at Capitol Reef NP is available in D. Binkley et al. 1997. Status of Air Quality and Related Values in Class I National Parks and Monuments of the Colorado Plateau. National Park Service. Denver, CO.